ICP DAS USA GW-7228 Quick Start Manual page 7

Get J1939 input data
Using the Modbus command as below:
FC4 Read multiple input registers (3xxxx) for AI
Example:
Read a value of one word in the address 30001.
[Request] (Byte0, Byte1... Byten) (Hex)
01 04 00 00 00 01
GW-7228 responds a value of one word in the address 30001.
[Response](Byte0, Byte1... Byten) (Hex)
01 04 02 12 34
Start or Stop sending J1939 output message
1、Using the Modbus command as below:
FC6 Write single register (4xxxx) for AO
Example: Start sending J1939 output message
In the address 42009, write the value in 0x00.
[Request Command] (Byte0, Byte1... Byten) (Hex)
01 06 07 D8 00
Example: Stop sending J1939 output message
In the address 42009, write the value in 0x01.
[Request Command] (Byte0, Byte1... Byten) (Hex)
01 06 07 D8 00
Or
2、Enable / Disable the Auto Transmission function as below, and upload to
GW-7228:
Figure 11: J1939 Auto Transmission function screen
31 CA(CRC)
B4 47(CRC)
00 08 85(CRC)
01 C9 45(CRC)
GW-7228 Quick Start v1.2 2011/05
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